Coaxial combustion products generator, turbine, and compressor



C. F. BACHLE May 6, 1952 COAXIAL COMBUSTION PRODUCTS GENERATOR, TURBINE, AND COMPRESSOR Filed April 20, 1946 mmvrox. Carl I. 506/249 14 TTOPNEXS Patented May 6, 1952 COAXIAL COMBUSTION PRODUCTS GENER- ATOR, TURBINE, AND COMPRESSOR Carl F. Bachle, Detroit, Mich., assignor to Continental Aviation & Engineering Corporation, Detroit, Mich., a corporation of Virginia Application April 20,

4 Claims. (01. 60-39-36) This invention relates to a gas turbine of the type which utilizes a mixture of burned gas and an.

Recent developments in the jet propulsion of aircraft emphasize the importance of research in gas turbines of the type which are run by a mixture of burned gas and air. In aircraft design, size and weight of the power plant are factors of primary importance. Any development, therefore, which enables the power plant to be reduced in size and, correspondingly, in weight without sacrificing power is important.

It is the object of this invention to set forth a gas turbine design which will be an efficient power plant, but which will permit important size and weight reductions without sacrificing power. This is accomplished by reducing the size of the combustion chamber. In a smaller combustion chamber, the problem of burning fuel and air is increased, and this invention solves that problem by mixing fuel and air before entering the compressor. Another prob-- lem involving size of the power plant is the intimate mixing of burned and/or burning gas with secondary air; this invention solves that problem by accomplishing the mixing in a region of high turbulence.

In the drawings:

Fig. 1 is a longitudinal section through the engine.

Fig. 2 is a developed view of the periphery of the compressor rotor; and

Fig. 3 is a detail sectional view along the line 3-3 of Fig. 1.

A rotary compressor 2 is shown mounted for rotation on a shaft 4 at one end of which is mounted a power utilizer orturbine wheel 6. Rotor 2 is made with two sets of passages, one set of these passages being formed by inlet openings 8 'in the hub or rotor 2 and immediately adjacent the axle 4, and outlet openings III in the periphery of rotor 2. The other set of passages'through rotor 2 has openings l2 adjacent the openings 8 and located farther from the shaft 4 than openings 8, and outlet openings I4. Some of this second set of passages are disposed on the opposite end of rotor 2. These passages are shown as having inlet openings I2 and outlet openings [4. It will be seen from Figs. 1 and 2 that outlet openings 14 are disposed on opposite sides of outlet openings 10. Diffuser vanes l are disposed in the path of the outlet openings.

An air duct 18 is arranged to supply air to inlet openings 8 and I2. Inlet openings [2' are 1946, Serial N0. 663,723

supplied with air through enveloping passages [8 which constitute the space formed between the outer extremities of combustion chamber 20 and casing 22. 5 A fuel injection nozzle 24 is disposed in air duct I6 preferably in such a manner as to limit the fuel-air mixture to inlet openings 8 in the rotor. To this end, nozzle 24 may be arranged in a shield 26 located in air duct [6.

The outside passages formed by openings l2l4 and l2"l4 may be shrouded or not as may seem desirable. It has been found in this invention that the open or unshrouded passages provide satisfactory performance.

As can be readily seen from Figs. 2 and 3, there are disposed radial vanes 28 and 30 in outlet openings Ill. In a practical embodiment of this invention rotor 2 may, if preferred, be constructed in two halves divided substantially along line 3-3 extended of Fig. 1, these two halves being bolted or otherwise fastened together. In this embodiment, the vanes 28 will be integral with one of the rotor halves and the vanes 30 will be integral with the other half, the vanes 28 and 30 alternating in the outlet opening I0. Vanes 28 and 3B are closely spaced together so as to have the effect of a flame-arresting means so that combustion of the fuel-air mixture will not take place inside rotor 2, in order that rotor 2 may be made of a very light and relatively soft material, such as aluminum.

In the preferred embodiment, just described, the set of passages made up by openings 8Hl has been set forth as the fuel-air passages, while ithe passages constituted by openings l2l4 and I2'-l4 are set forth as the auxiliary air passages. If desired of course the function of the two sets of passages may be interchanged so that passages 8-10 carry auxiliary air and the passages [2-H and l2'-I4 carry fuel and air. It will be understood however that the flamearresting means described will be disposed in the fuel-air passages. An ignition plug 32 of any of a number of satisfactory types may be provided for initial ignition of the fuel-air mixture in combustion chamber 20.

Operation place in the chamber 20. Combustion inside rotor 2 is prevented by the flame-arresting action of closely spaced radial vanes 28 and 30. Auxiliary air passes through the passages l2l4 and, by the way of passages l8, through passages I2--l4 in such a manner that auxiliary air issues from the rotor periphery in two streams with the burning fuel-air mixture issuing from the rotor between the two streams of auxiliary air. This arrangement accomplishes the purpose of helping to insulate the combustion chamber against heat losses; also, this arrangement accomplishes intimate mixing of burning fuel-air and auxiliary air by mixing them in a region of extremely high turbulence, i. e., adjacent the periphery of fast rotating rotor 2. The engine is further guarded against heat losses by having air for passages l2'-I4 surround the combustion chamber by virtue of annular space or passage l8. This feature serves also as a preheater for some of the auxiliary air. The arrangement of two jets of auxiliary air disposed on opposite sides of the fuel-air mixture serves the additional purpose of keeping the rotor 2 at a relatively cool temperature. The entire arrangement permits the use of an extremely light weight material for rotor 2 and, because of the mixture in a region of high turbulence, enables the use of a relatively small but efficient combustion chamber 20.

The intimately mixed gases and auxiliary air issue from the combustion chamber through circumferentially spaced nozzles 34 to impinge upon the turbine wheel 6. Nozzles 34 alternate with similarly circumferentially spaced air passages 36, which afford communication between space l8 and inlet openings I2. Some auxiliary air from space l8 by-passes, or passes around, the turbine wheel, as can be seen from Fig. 1.

I claim:

1. An internal combustion engine comprising a fixed casing structure having an annular combustion chamber, a shaft rotatably supported axiallyof said casing, a turbine wheel mounted on said shaft and having turbine blades adapted to be disposed in the fluid stream exhausted from said combustion chamber, a compressor rotor mounted on said shaft and having separate passages all terminating in axially spaced outlets at the periphery of the rotor, an air duct carried by the casing structure and arranged to supply air to the rotor and having concentric inner and outer air passages terminating in outlets aligned with the inlets of a like number of passages in said rotor, a source of fuel supply, and means to supply fuel mixture to one of said rotor passages and air to the others of said rotor passages, all said rotor passages being separated and discharging directly into said combustion chamber.

2. An internal combustion engine comprising a fixed casing structure having an annular combustion chamber, a shaft rotatably supported axially of said casing, a turbine wheel to be disposed in the fiuid stream exhausted from said combustion chamber, a compressor rotor mounted on said shaft and having separate passages all terminating in axially spaced outlets at the periphery of the rotor, an air duct carried by the casing structure and arranged to supply air to the rotor and having concentric inner and outer air passages terminating in outlets aligned with the inlets of a like number of passages in said rotor, a source of fuel supply, and means to supply fuel to one of said casing air passages, whereby to supply a fuel mixture to one of said rotor passages and air to the others of said rotor passages, all said rotor passages being separated and discharging directly into said combustion chamber, said casing structure provided with an extended passage connected with the air passage supplying air alone to said rotor, said extended passage encompassin the combustion chamber and. communicating with anotherof said rotor passages having an inlet disposed on the rotor end opposite to the said other rotor passage inlets.

3. An internal combustion engine comprising a fixed casing structure having an annular combustion chamber, a shaft rotatably supported axially of said casing, a turbine wheel mounted on said shaft and having turbine blades adapted to be disposed inthe fluid stream exhausted from said combustion chamber, a compressor rotor mounted on said shaft and having separate passages all terminating in axially spaced outlets at the periphery of the rotor, an air duct carried by the casing structure and arranged to supply air to the rotor and having concentric inner and outer air passages terminating in outlets aligned with the inlets of a like number of passages in said rotor, a source of fuel supply, and means to supply fuel to said inner air passage whereby to supply a fuel mixture to the rotor passage aligned therewith, and which is disposed in said rotor intermediate the others of said rotor passages, one of said other rotor passages having inlet ends aligned with said outer air passage, said casing structure provided with an extended passage connected with the said outer air passage and encompassing the combustion chamber and communicating with another of said'other rotor passages, said third rotor passage having an inlet disposed on the rotor end opposite to said other rotor passage inlets.

4. An internal combustion engine comprising a fixed casing structure having an annular combustion chamber, a shaft rotatably supported axially of said casing, a turbine wheel mounted on said shaft and having turbine blades adapted to be disposed in the fluid stream exhausted from said combustion chamber, a compressor rotor mounted on said shaft and having separate passages all terminating in axially spaced outlets at the periphery of the rotor, an air duct carried by the casing structure and arranged to supply air to the rotor and having concentric inner and outer air passages terminating in outlets aligned with the inlets of a like number of passages in said rotor, a source of fuel supply, and means to supply fuel to said inner air passage whereby to supply a fuel mixture to the rotor passage aligned therewith, and which is disposed in said rotor intermediate the other of said rotor passages, one of said other rotor passages having inlet ends aligned with said outer air passage, said casing structure provided with an extended passage connected with the said outer air passage and encompassing the combustion chamber and communicating with another of said other rotor passages, said third rotor passage having an inlet disposed on the rotor end opposite to said other rotor passage inlets, said fuel mixture rotor outlet comprising interlaced staggered baflles serving as flame arresting means, and fixed baflies carried by the casing and extending inwardly from the walls of the combustion chamber adjacent to. and solely overlying the outlets of the air passages in said rotor to create turbulences and resulting in immediate commingling of the air streams and intermediate fuel mixture stream 5 in that portion of the combustion chamber adja- Number cent to the periphery of said rotor. 2,419,598 CARL F. BACHLE. 2,476,218 2,477,683 REFERENCES CITED 5 The following references are of record in the Number fi 1e of this patent 648,107 UNITED STATES PATENTS 635,330 Number Name Date 10 74 2,256,198 Hahn Sept. 16, 1941 44, 2,404,707 Heppner July 23, 1946 171,685

Name Date Schey Apr. 29, 1947 Prime July 12, 1949 Birmann Aug. 2, 1949 FOREIGN PATENTS Country Date France Aug. 7, 1928 France Apr. 7, 1930 Germany May 17, 1932 Germany May 14, 1937 Great Britain June 22, 1922 

